Study of the Antibacterial Activity of Methanolic and Aqueous Extracts of Myrtus communis on Pathogenic Strains Causing Infection

Background Medicine plants have been used as sources of medicine in virtually all cultures. During the last decade, the use of traditional medicine (TM) has been expanded globally and is gaining popularity. Objectives The antimicrobial activities of methanol and water extracts of Myrtus communis L. leaves were evaluated in this study. Materials and Methods In this experimental study, the tests were carried out using disk agar diffusion method at four extract concentrations (5, 10, 15 and 20 mg/mL). The MICs and MBCs of the extracts of M. communis were determined by agar dilution method. Average results were reported as the mean and standard error (mean ± SE) and SPSS-18 statistical software, oneway ANOVA followed by Turkey’s test were used to do inter-group comparison, while considering P ≤ 0.05 as the significance level. Results Methanol extract of M. communis exhibited significant antibacterial activity in the concentration of 20 mg/mL (P ≤ 0.05) against Staphylococcus epidermidis and Enterococcus faecalis with a greater inhibition zone of 20 mm, while a 14 mm zone of inhibition was observed in Escherichia coli and Shigella flexneri. The minimum inhibitory concentration (MIC) of the extracts ranged between 2 mg/mL and 128 mg/mL while the minimum bactericidal concentration (MBC) ranged between 4 mg/mL and 256 mg/mL. Conclusions The study showed that species, strains and concentrations of M. communis extract are of those factors that may influence the sensitivity of the tested bacteria. A significant correlation was observed between zone of inhibition and concentration of extract.